I have a 1977 S&S with over 2000 hours that I have owned since 1978 with 65 hours. Have had no problems with the transmission, C71 1to1, until this weekend. I was crusing about 30 mph and the engine rpm started to rise and the boat slowed down. Turned the engine off and found that the trans had lost it's fluid. The fluid is in the bottom of the boat and I can find no place that it came out?? The dipstick was tight and no evidence of broken hoses, leaks, and no oil around the breather?? When the problem started the shifter would not go back into neutral but then loosened up and now it moves freely. I am stuck, does anyone have a possible cause and solution??